Tool for slotting commutators



W. L. WEBER TOOL FOR SLOTTING COMMUTATORS Dec. 16, 19241 1,519,228

Filed Oct. 29, 1923 p 1 v WM Patented Dec. 16, 1924.

UNITED STATES WILLIAM L. WEBER, OF CHICAGO, ILLINOIS.

TOOL FOR SLOTTING COMMUTATOR-S.

Application filed October 29, 1923. Serial No. 671,360.

To all whom it may concern:

Be it known that I, WILLIAM L. VVEBER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Tools for Slotting Commutators, of which the following is a specification.

This invention relates to tools for slotting oommutators, or in other words, for undercutting the mica or other insulation between the segments of the commutator of a dynamo electric machine.

One of the primary purposes of this invention is to provide a tool which can be employed to rapidly and accurately perform the slotting or undercutting operation, thus enabling the slotting to be done rapidly and economically.

For the purpose of facilitating an understanding of my invention, I have illustrated on the accompanying drawings a preferred embodiment thereof.

Referring to the drawings:

Fig. 1 is a perspective view of my improved tool; and

Fig. 2 is a fragmentary transverse sec- I tional View of the commutator.

The commutator comprises, as is customary, a series of segments 3, usually made of copper, which are separated one from the other by insulators 4, made of mica or other p suitable insulating material.

The successful operation of a machine of this character necessitates close contact between the commutator segments and the brushes beneath which they revolve, and this contact is best maintained when the outer edges of the insulators terminate somewhat within the circumference of the commutator segments. Since the segments, however, wear down faster than the insulators, continued use of a commutator results in the projection of th insulators slightly beyond the perimeter of the commutator segments, and this projection causes sparking of the brushes and inefficient and unsatisfactory operation of the machine.

Various machines and devices, more or less complicated in construct-ion and operation, have heretofore been devised for slotting or undercutting the mica insulators to bring their outer edges within the perimeter of the commutator segments. My present tool is designed to accomplish this result with rapidity and economy, and aims, furthermore, to produce accurate undercutting, which is conducive to efficiency of the machine. My improved tool, furthermore is designed to be used upon the commutator without removing the commutator from its bearings, and therefore the undercutting operation with my improved tool requires much less time and labor than is required when the commutator must be removed from the stator and placed upon a special machine by which the undercutting is performed.

My improved tool comprises a bar 5 of steel or other suitably strong material, the bar being of such size that the shank 6 projecting from the handle 7 possesses a limited degree of flexibility and resiliency which permits slight vibratory and yielding movements of the cutter as it is dragged along the commutator.

This bar is curved reversely, as indicated at 8, into hook shape, the extremity of the hook being disposed toward the handle and diverging slightly from the shank 6. While the shank may be of any desired cross sectional shape, the extremity of the hook is substantially triangular in cross section, having an acute angle at the bottom, so that the lower narrow edge 9 is adapted to travel between adjacent commutator segments. The extremity of the hook is tempered to rovide a durable cutting point 11, from which point the end face 12 is beveled back toward the arch of the hook, so that the cutting point 11 projects a limited distance.

When the commutator has been used for some time the outer edges of the insulators are disposed flush with or project even slightly beyond the perimeter of the commutator segments, as illustrated in Fig. 2. To remedy this condition is the purpose of my improved tool, and the operation of the tool is substantially as follows:

Without removing the commutator from its bearings, the operator, standing at the outer end of the commutator, grasps the handle of the tool and inserts the point 1.1 into one of the insulators at the inner end of the commutator. tie then presses downwardly upon the tool and at the same time pulls it toward him, with the result that the cutting point 11 travels between adjacent commutator segments and cuts down the edge of the insulator so as to provide a groove therein, as indicated by reference character 13. This operation is performed upon each insulator of the commutator, thus bringingtherouter edges of the insulators Well Within the perimeter of the commutator segments. The operationmay beperformed With considerable rapidity, and since re moval of the commutator from its loearlngs 1s unnecessary, the time and labor requlred t0 reeondlt on the commutator are 10 reduced to a minimum.

I claim: A tool for slotting co mmutators comprisinga handle and. a bar projectingiherefrom,

tween its endstto dispose said cutting point toward said handle.

7 WILLIAM L. WEBER. 

